Pleiotropic Roles of Polyglycerolphosphate Synthase of Lipoteichoic Acid in Growth of Staphylococcus aureus Cells

Abstract

Lipoteichoic acid (LTA) is one of two anionic polymers on the surface of the gram-positive bacterium Staphylococcus aureus . LTA is critical for the bacterium-host cell interaction and has recently been shown to be required for cell growth and division. To determine additional biological roles of LTA, we found it necessary to identify permissive conditions for the growth of an LTA-deficient mutant. We found that an LTA-deficient S. aureus Δ ltaS mutant could grow at 30°C but not at 37°C. Even at the permissive temperature, Δ ltaS mutant cells had aberrant cell division and separation, decreased autolysis, and reduced levels of peptidoglycan hydrolases. Upshift of Δ ltaS mutant cells to a nonpermissive temperature caused an inability to exclude Sytox green dye. A high-osmolarity growth medium remarkably rescued the colony-forming ability of the Δ ltaS mutant at 37°C, indicating that LTA synthesis is required for growth under low-osmolarity conditions. In addition, the Δ ltaS mutation was found to be synthetically lethal with the Δ tagO mutation, which disrupts the synthesis of the other anionic polymer, wall teichoic acid (WTA), at 30°C, suggesting that LTA and WTA compensate for one another in an essential function.